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    <title>Document</title>
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    <script>
      function fn(params) {
        params.header = {
          // 先把之前的header 数据 解构出来
          ...params.header,
          auth: 'token',
        }
        // console.log(params)
        // params.header.auth // undefined
      }
      fn({
        url: 'aabbcc',
        header: {
          a: 1,
          b: 2,
        },
      })
    </script>
  </body>
</html>
